Coproduction of hydrogen and pyruvic acid on 0D-2D CoP–ZnIn2S4 from lactic acid photoreforming

Abstract

Photocatalytic hydrogen production in the presence of a sacrificial agent is emerging as a promising strategy for the solar-to-hydrogen process. However, the lack of a bifunctional photocatalyst to simultaneously produce hydrogen and selectively convert sacrificial agents significantly increases the cost of photocatalytic hydrogen production. Herein, we design a two-dimensional (2D) nanosheet-assembled ZnIn2S4 flower loaded with 0D CoP nanodots as an electron collector. The 0D-2D assembled heterojunction structure significantly enhances the spatial separation of photogenerated electron-hole pairs and endows the as-fabricated photocatalyst with dual functionality. As a result, the optimized photocatalyst shows excellent hydrogen production (233.78 μmol/h) by using lactic acid as the sacrificial agent. More importantly, lactic acid is selectively converted into pyruvic acid simultaneously with the conversion of 80.90 % after 24 h. The highest selectivity of 93.9 % is also achieved after 3 h reaction. The feasibility study of present work demonstrated that the employed system is profitable, in which the largest amount of annual revenue is generated by pyruvic acid (99 %), while H2 accounts for 1 % of the annual revenue. The present work sheds new light on the coproduction of sustainable hydrogen and value-added chemicals with the rational design of bifunctional photocatalysts.